If you toss batteries loose into your carry-on, there is a risk that the contacts might touch each other or something else metal. This can cause a short circuit that can lead to a fire inside an aircraft. To avoid the danger, wrap each battery separately in plastic to keep the contacts from ever touching. Here are some other battery safety tips:
- Always carry batteries in your carry-on luggage, where they are accessible, in case of fire.
- Never pack batteries in a case that is tightly overpacked. Such pressure can cause overheating of the battery.
- If you are carrying an electrical device containing a battery, make sure that other items inside your bag cannot inadvertently turn on the device. If it turns "on" while packed in with other items, overheating could result, possibly causing a fire.
- When packing batteries, don't allow heavy items to rest on top of them, or pack the carry-on too tightly. Keep sharp objects away from the batteries to avoid puncturing.